CN106659354B

CN106659354B - Heating circulation type drying module of dish washer

Info

Publication number: CN106659354B
Application number: CN201680002033.7A
Authority: CN
Inventors: 洪禹; 禹相宇; 柳善化
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2015-06-11
Filing date: 2016-06-10
Publication date: 2020-05-05
Anticipated expiration: 2036-06-10
Also published as: CN106659354A; EP3307133A1; KR20160146091A; EP3307133B1; EP3307133A4; US20170196431A1; WO2016200198A1; KR101792513B1; US10568487B2

Abstract

Disclosed is a heating cycle type drying module of a dishwasher using a fan module and a PTC heater. The dish washer includes: a cabinet defining an exterior; a tub disposed in the cabinet; a door for opening or closing the tub; a flow path unit for circulating air inside the tub through a suction port and an exhaust port communicating with the tub; a suction duct for communicating with the suction port; an exhaust conduit for communicating with the suction conduit and the exhaust port; at least two heaters disposed inside the exhaust duct to heat air; and a fan for supplying air to the heater. The dishwasher may achieve improved drying performance via adjustment of the temperature of air to be discharged, and may reduce power consumption via omission of a rinsing water heating process.

Description

Heating circulation type drying module of dish washer

Technical Field

The present invention relates to a dishwasher, and more particularly, to a dishwasher that removes water from dishes by heating and circulating air inside a tub after the circulation of the dishwasher is finished.

Background

A dishwasher is an electric home appliance that removes residual food adhered to the surface of dishes using high-pressure washing water sprayed from a nozzle. The dishwasher includes, for example, a tub defining a washing container, and a sump mounted on a lower surface of the tub to store washing water therein. The dishwasher sequentially performs a washing cycle, a rinsing cycle, and a drying cycle.

The dishwasher having a drying function includes a drying device for removing moisture from the dishes by supplying heated air into the tub. The drying device may include, for example, a heater for heating air, and a blower for blowing the air heated by the heater. In addition, a dehumidifying operation of humid air during drying is generally performed using a zeolite or a heat pump system.

The conventional drying method includes a rinsing course. After the water is heated in the rinsing course, the heated water is discharged into the tub to allow the dishes to store thermal energy, thereby evaporating moisture on the surfaces of the dishes using the latent heat of the dishes. Therefore, a large amount of electricity is consumed when the water is heated.

Disclosure of Invention

Technical problem

Accordingly, the present invention has been made keeping in mind the above problems of the related art, and an object of the present invention is to achieve reduction of power consumption by omitting a water heating course and high drying performance using only hot air, since water on the surface of dishes is evaporated by heating air using only a drying module without using a heated rinsing course, which is a typical drying method of a dishwasher.

Another object of the present invention is to achieve an improvement in drying performance by adjusting the temperature of drying air based on the kind and number of objects to be dried.

Another object of the present invention is to achieve uniform drying of different areas inside a tub by adjusting a flow rate of drying air so as to induce a change in a circulation pattern of air inside the tub.

A further object of the present invention is to achieve reduction of power consumption required for dehumidification by discharging humid air circulating inside a tub to the outside.

Technical scheme

According to an aspect of the present invention, the above and other objects can be accomplished by the provision of a dishwasher including: a cabinet; a tub disposed in the cabinet to provide a washing space; a door for opening or closing the tub; a flow path unit for circulating air inside the tub through a suction port and an exhaust port communicating with the tub; a suction duct for communicating with the suction port; an exhaust duct for communicating with the suction duct and the exhaust port; at least two heaters arranged inside the exhaust duct for heating air; and a fan for supplying air to the heater. Since the dishes are dried using the air, power consumption may be reduced, and since the temperature of the drying air is adjustable, drying efficiency may be increased. In addition, the flow rate of air may be adjusted by adjusting the rotation of the fan, and power consumption for dehumidification may be reduced by discharging humid air to the outside through the opened door.

The heaters may be controlled independently of each other to adjust the temperature of air and increase drying performance.

The door may be opened at least once during operation of the heater, which may reduce power consumption.

When the air inside the tub reaches the reference humidity, the door may be kept open, and the humidity inside the tub may be lowered without generating power.

The door may be kept open when the air inside the tub reaches a designated temperature.

The heater may be a Positive Temperature Coefficient (PTC) heater, which may reduce power consumption.

The RPM of the fan may be changed at least once during the operation of the heater, which may allow the drying air to be uniformly distributed inside the tub.

The door may be opened in synchronization with a change in RPM of the fan.

The flow path unit may include: a suction flow path for interconnecting the suction port and the suction duct; and an exhaust flow path for interconnecting the exhaust port and the exhaust duct, and each of the suction flow path and the exhaust flow path may extend upward from the suction port or the exhaust port by a designated distance so as to prevent introduction of wash water.

The suction port may be positioned higher than the exhaust port, which serves to promote circulation of air inside the tub.

The exhaust flow path may be provided with ribs to assist the flow of air from the exhaust duct to the exhaust port.

Each of the suction port and the exhaust port may be provided at an end thereof with a drain hole to drain the washing water introduced into the suction port or the exhaust port to the inside of the tub.

Each of the suction port and the exhaust port may have a circular passage in a central portion thereof, and a plurality of tapered passages may be provided around the circular passage, which allows the drying air to be uniformly supplied into the tub.

The dishwasher may further include an upper rack disposed inside the tub, and a lower rack disposed below the upper rack, and the exhaust port may be located at the same height as the lower rack, which allows the drying air to be directly supplied to the dishes, resulting in improved drying performance.

The circumferential surfaces forming the suction port and the exhaust port may be inclined toward the tub so as to drain the washing water introduced into the suction port and the exhaust port toward the inside of the tub.

According to another aspect of the present invention, there is provided a method of controlling a dishwasher, the method including: setting a cleaning process and drying time; drying the bowls and dishes; measuring humidity inside the dishwasher, comparing the measured humidity with a preset reference humidity; and opening the door when the humidity inside the dishwasher is higher than or equal to the reference humidity.

When the humidity measured in the measurement is lower than the reference humidity, the drying may be continuously performed.

The control method may further include: the humidity inside the dishwasher is compared with a reference humidity after the door is opened, and the door may be kept open when the humidity inside the dishwasher is higher than the reference humidity, and may be closed when the humidity inside the dishwasher is lower than the reference humidity.

Advantageous effects

By omitting the process of heating the final rinse water at a high temperature, the present invention has an effect of reducing energy use by 20-30% compared to conventional energy use.

The present invention has the effect of improving drying performance by independently controlling two or more heating units in order to adjust the temperature of air to be discharged.

The present invention can adjust the flow rate of air differently for different operation periods by changing the RPM of the fan in the corresponding operation, and can dry different regions in the drying rack by changing the circulation flow pattern of the air inside the tub.

The present invention can prevent additional power consumption for dehumidification by discharging humid air to the outside through the opened door.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.

In the drawings:

fig. 1 is a sectional view illustrating a dishwasher according to an embodiment of the present invention;

fig. 2 is a perspective view illustrating a flow path unit and a heating unit attached to a side surface of a dishwasher according to an embodiment of the present invention;

FIG. 3 is a perspective view illustrating a flow path unit and a heating unit;

FIG. 4 is a perspective view illustrating the shape of the cap;

FIG. 5 is a perspective view illustrating a drain hole in the cap

FIG. 6 is a perspective view illustrating a heating unit; and is

Fig. 7 is a flowchart illustrating a control method of a dishwasher.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Meanwhile, the configuration of an apparatus or a control method thereof, which will be described below, is given only for the purpose of describing embodiments of the present invention, and is not intended to limit the scope of the present invention. Throughout the specification, the same reference numerals denote the same constituent elements.

As illustrated in fig. 1, a dishwasher 100 according to an embodiment of the present invention basically includes: a cabinet 1 defining an external appearance of the dishwasher; a tub 2 provided in the cabinet 1 to provide a washing space; a sump 3 coupled under the tub 2 to store washing water therein; and a pump 4 for pumping the water in the sump 3. The cabinet 1 includes a door 11 for opening or closing the tub 2.

A washing chamber 21 for receiving dishes therein is defined in the tub 2. A plurality of shelves 22 on which dishes can be placed are installed in the washing chamber 21. The shelf 22 includes an upper shelf 221 and a lower shelf 222.

The washing water stored in the sump 3 passes through the connection pipe 31 and is sprayed to the dishes placed on the rack 22 by the spray arm 32. The spray arm 32 includes an upper arm 321 located below the upper shelf 221, and a lower arm 322 located below the lower shelf 222. The upper and lower arms 321 and 332 are independently and rotatably installed, and each of the spray arms 32 is provided with a plurality of nozzles for spraying wash water toward the dishes.

The washing water stored in the sump 3 may be selectively or simultaneously supplied to the upper arm 321 and the lower arm 322 through the connection pipe 31 by the pump 4.

The washing water stored in the sump 3 is introduced through the water supply pipe 41, and after having been used to wash dishes, the washing water is discharged to the outside of the dishwasher 100 through the drain pipe 42. The amount of water supplied and drained is adjusted using respective valves (not shown) installed on the water supply pipe 41 and the drain pipe 42.

Meanwhile, fig. 2 illustrates a shape of the drying module 200 included in the dishwasher 100, and fig. 3 also illustrates a shape of the drying module 200. The drying module 200 is composed of a flow path unit 5 for drying dishes and a heating unit 6.

The flow path unit 5 serves as a passage for transferring air inside the tub 2 to the heating unit 6 or transferring air heated in the heating unit 6 to the inside of the tub 2. The heating unit 6 serves to heat air inside the tub 2 introduced thereinto through the flow path unit 5.

The flow path unit 5 may be located on one surface of the cabinet 1 that may communicate with the inside of the tub 2, and more particularly, may be located on a side surface or a rear surface of the cabinet 1, in addition to the upper and lower surfaces of the cabinet 1 defining the appearance of the dishwasher 100.

The heating unit 6 is provided in communication with the flow path unit 5. In addition, although the heating unit 6 is not limited in position as long as it is located inside the dishwasher 100, considering that the remaining region in which the tub 2 is installed is important in defining the washing space, the heating unit 6 may be located in a lower region of the dishwasher 100, which has an available space because the sump 3 is installed in the lower region of the dishwasher 100.

The drying module 200 may be detachably coupled to the dishwasher, or integrally formed with the dishwasher, or may be separately installed at an outside of the dishwasher.

Referring to fig. 3, the flow path unit 5 includes, for example: a suction port 51 serving as an inlet for sucking air circulating inside the tub 2; an exhaust port 52 serving as an outlet for discharging the drawn air to the inside of the tub 2 after the air is dried; a suction flow path 53 serving as a passage for communicating with the suction port 51 and delivering air to the heating unit 6; an exhaust flow path 54 serving as a passage for communicating with the exhaust port 52 and transferring heated air from the heating unit 6 to the exhaust port 52; ribs 55 for promoting smooth flow of air to the suction flow path 53 and the exhaust flow path 54; and a cap (cap)56 provided on the suction port 51 and the exhaust port 52 to assist in smoothly collecting and exhausting air.

The rib 55 is arranged in the suction flow path 53 or the exhaust flow path 54 so as to contribute to a stable flow of air. More specifically, a plurality of ribs 55 are arranged in the longitudinal direction of the suction flow path 53 and the exhaust flow path 54. The ribs 55 may be installed at a constant distance inside the suction flow path 53 and the exhaust flow path 54.

Referring to fig. 5, at least one of an interface where the tub 2 and the suction port 51 are connected to each other and an interface where the tub 2 and the exhaust port 52 are connected to each other is provided with a slope 511 so as to allow washing water or contaminants introduced into the suction port 51 and the exhaust port 52 to be easily discharged to the inside of the tub 2.

Referring to fig. 4, the cap 56 provided on the suction port 51 or the exhaust port 52 may cause the air sucked through the suction port 51 to be uniformly collected and may cause the hot air discharged through the exhaust port 52 to be uniformly distributed inside the tub 2. In addition, the cap 56 functions to prevent wash water and contaminants from depositing in the direction of gravity for extended periods of time.

The cap 56 may be detachably coupled to the suction port 51 or the exhaust port 52, or integrally formed with the suction port 51 or the exhaust port 52. In the case of the detachable cap 56, a plurality of hooks 561 are provided on the periphery of the cap 56 to facilitate easy coupling with the suction port 51 and the exhaust port 52.

In order to prevent the cleaning water and the contaminants from being deposited in the suction port 51 or the exhaust port 52, the cap 56 has a drain hole 562. The washing water and the contaminants moving along the slope 51 provided on the suction port 51 or the exhaust port 52 are discharged through the drain hole 562.

The cap 56 is provided with a circular passage 564 and a plurality of tapered passages 563 in a central portion thereof. The circular passage 564 and the tapered passage 563 may allow the air sucked through the suction port 51 to be uniformly collected and may allow the hot air discharged through the exhaust port 52 to be uniformly distributed in the inside of the tub 2.

The tapered channel 563 may have a generally trapezoidal shape in cross-section, and the tapered channel 563 may form a single circle so as to surround the circular channel 564.

The cap 56 is configured such that the cross section of the circular passage 564 closer to the tub 2 is larger than the cross section of the circular passage 564 closer to the suction port 51 or the exhaust port 52. In contrast, the cross section of the tapered passage 563 closer to the tub 2 is smaller than that of the tapered passage 563 closer to the suction port 51 or the exhaust port 52. That is, when the heated air is discharged from the exhaust flow path 54 to the tub 2, the circular passage 564 is gradually widened, but the tapered passage 563 is gradually narrowed. Similarly, when the air inside the tub 2 is introduced into the suction flow path 53, the circular passage 564 is gradually narrowed, but the tapered passage 563 is gradually widened.

Fig. 6 is a perspective view of the heating unit 6. The heating unit 6 serves to heat air inside the tub 2 supplied from the flow path unit 5, so that the heated air is supplied to the flow path unit 5 again. In addition, the heating unit 6 may adjust the temperature to which the air is heated and may also adjust the flow rate of the heated air.

The heating unit 6 may include: a heater 61 for heating the air supplied from the flow path unit 5; a fan 62 for promoting circulation of air; a motor 63 for rotating the fan 62; a suction duct 64 for communicating with the flow path unit 5 so as to receive air; and an exhaust duct 65 for communicating with the flow path unit 5 to discharge the heated air.

The heating unit 6 may include a plurality of heaters 61 for heating the supplied air, and the respective heaters 6 may be independently controlled. Additionally, the respective heater may be a Positive Temperature Coefficient (PTC) heater.

A PTC heater is a heater that can be controlled such that the temperature does not increase when a given level is reached and that has very low power consumption compared to other kinds of heaters. In addition, the temperature of the air to be discharged may be adjusted by independently controlling the two or more heaters 61. In the present invention, by using the PTC heater, a separate temperature sensor is not required, and the temperature of the air to be discharged can be adjusted without using a controller.

In the embodiment of the present invention, two heaters 61 are provided, including a first heater 611 and a second heater 612. The temperature of the air can be increased or decreased by independently controlling the respective heaters 61.

As the drying process is performed, it becomes more difficult to evaporate the remaining moisture. To solve this problem, two or more heaters 61 may be provided such that the number of the heaters 61 operated is gradually increased while the drying course is performed. This is because one heater 61 may not be sufficient to evaporate the moisture remaining inside the tub toward the end of the drying process. Thus, when all of the two or more heaters 61 are operated, additional heat required to evaporate the moisture can be obtained.

The heater 61 may be installed at any position inside the heating unit 6 as long as air flows through the position. In an embodiment of the present invention, the heater 61 is located inside the exhaust duct 65.

Since the fan 62 is also used to promote the circulation of air, the fan 62 may be installed at any position inside the heating unit 6 as long as it can adjust the flow rate of air. In an embodiment of the present invention, a heater 61 may be installed between the outlet of the exhaust duct 65 and the fan 62 so that air can be directly blown to the heater 61.

The RPM of the fan 62 is controlled by the BLDC motor 63. The BLDC motor may be functionally used to adjust the flow rate differently for different operation periods by changing the RPM in the corresponding operation, and may allow different areas in the drying rack 22 to be dried by changing the circulation flow pattern of the air inside the tub 2.

Due to the fact that the lower shelf 222 and the exhaust port 52 have the same height and the fact that the sectional shape of the cap 56 provided on the exhaust port 52 is defined by the tapered passage 563, the flow of the air inside the tub 2 can be adjusted only by adjusting the RPM of the fan 62. Considering the flow of the air discharged from the exhaust port 52, the heated air discharged from the exhaust port 52 moves upward through the lower shelf 222, and thereafter returns to the suction port 51. That is, the discharged air circulates inside the tub 2.

When the fan 62 is rotated at the first RPM, the dryness of the dishes placed on the lower rack 222 increases, and among the washing objects received in the upper rack 221, the dryness of the dishes located in an area distant from the suction port 51 is higher than the dryness of the dishes located in an area close to the suction port 51. When the fan 62 is rotated at a second RPM lower than the first RPM, the dryness of the dishes on the upper rack 221 is higher in a region close to the suction port 51 than in a region far from the suction port 51.

That is, in case of dishes placed on the lower rack 222, as the RPM of the fan 62 increases, the drying course is rapidly performed. In the case of the dishes placed on the upper rack 221, the dishes in the area distant from the suction port 51 have higher dryness when the RPM of the fan 62 corresponds to the first RPM, and the dishes in the area near the suction port 51 have higher dryness when the RPM of the fan 62 corresponds to the second RPM.

Accordingly, since the motor 63 varies the RPM to control the flow rate of the air, all the dishes inside the tub 2 can be uniformly dried. The RPM of the fan 62 may be changed at least once during the operation of the heater 61.

The suction duct 64 communicates with the suction flow path 53 of the flow path unit 5, and the exhaust duct 65 communicates with the exhaust flow path 54 of the flow path unit 5. The exhaust duct 65 may include a first housing 651 and a second housing 652, and the second housing 652 may communicate with the suction duct 64.

Although all of the heaters 61 and the fans 62 may be disposed inside the first and

second housings

651 and 652 constituting the exhaust duct 65, the present invention is not limited thereto.

The vent pipe 65, in which the PTC heater is incorporated, is formed of polyphenylene sulfide (PPS) material that can withstand high temperature.

Considering briefly the overall flow of air, the air inside the tub 2 is introduced into the flow path unit 5 through the suction port 51. Air moves from the suction port 51 to the suction duct 64 through the suction flow path 53. The air inside the suction duct 64 passes through the two or more heaters 61 inside the exhaust duct 65 via the operation of the fan 62. The air heated while passing through the heater 61 is moved from the exhaust duct 65 to the exhaust port 52 through the exhaust flow path 54 of the flow path unit 5 to be thereby discharged to the inside of the tub 2. As described above, the flow of air discharged to the inside of the tub 2 is changed inside the tub 2 by the BLDC motor 250 based on the RPM of the fan 62.

As the air continuously circulates inside the tub 2, the air becomes gradually damp. In order to remove the humid air, the door 30 may be opened while the drying course is performed (in other words, while the heater is operated). By opening the door 11 at least once during the operation of the heater 61, air that becomes humid while circulating inside the tub 2 can be discharged to the outside of the dishwasher 1.

All of the two or more heaters 61 may be operated in synchronization with the opening of the door 11. This serves to prevent the temperature inside the tub 2 from being lowered due to heated air inside the tub 2 being discharged to the outside when the door 11 is opened. In addition, this serves to allow the moisture remaining inside the tub to be more rapidly evaporated through the operation of the two or more heaters 61.

In addition, the RPM of the fan 62 may be increased in synchronization with the opening of the door 11, as compared to before the opening of the door 11. When the RPM of the fan 62 is increased in synchronization with the opening of the door 11, the flow rate of the air is increased, which ensures more smooth discharge of the humid air.

Fig. 7 illustrates an embodiment of a control method relating to the opening of the door 11. The setting of the washing course is an operation in which the user can select the washing course in advance based on the kind of laundry. The set drying time is an operation in which the user can select the total drying time of the laundry in advance.

Considering the algorithm in detail, the drying operation S20 is performed after the washing course and the drying time (S10) are set. The humidity H inside the tub is frequently measured (S30) while the drying operation S20 is performed, and the measured humidity H is compared with a preset reference humidity Hm (S40). When the comparison result is H > Hm, the door is opened (S50). When the comparison result is H < Hm, the drying operation is continuously performed (S20).

Although the reference humidity Hm may be set to a humidity at which water vapor is saturated, that is, a humidity at which evaporation does not occur any more, in some cases, the reference humidity Hm may be set to a humidity immediately before water vapor saturation in terms of drying efficiency.

When the door 11 is opened (S50), the humidity H inside the tub is continuously compared with the reference humidity Hm (S60). When the humidity H is higher than the reference humidity Hm, the door is kept open. When the humidity H is lower than the reference humidity Hm, the door is closed (S70).

After the door is closed (S70), the drying time set at the start of washing is compared with the actual execution time of the drying operation (S80). As long as the execution time of the drying operation does not exceed the set time, the drying operation is continuously executed (S20). When the execution time of the drying operation exceeds the set time, the entire washing cycle is ended.

The embodiment related to the opening of the door is simplified and prevents additional power consumption for dehumidification compared to existing dehumidification methods. Meanwhile, the door 30 may be set to be opened when the RPM of the fan 62 is changed.

In another embodiment related to dehumidification, a water tank (not illustrated) may be installed in a space in the flow path unit 5, which surrounds the suction port 51 and the suction flow path 53. The water supplied to the water tank before drying is heat-exchanged with the humid air that has been introduced into the suction port 51 after being circulated inside the tub 2. Before being introduced into the suction duct, the condensed water generated via heat exchange in the suction port 51 and the suction flow path 53 is discharged from a condensed water discharge hole (not illustrated) formed at an end of the suction flow path.

The present invention may be modified and implemented in various forms, and the scope of the present invention is not limited to the above-described embodiments. Therefore, these modifications should be construed as falling within the scope of the present invention as long as they include the constituent elements of the claims of the present invention.

Modes for the invention

As noted above, the associated descriptions have been discussed fully above in the context of "detailed description of the invention".

Industrial applicability

As described above, the present invention may be fully or partially applied to a dishwasher having a heating cycle type drying module.

Claims

1. A dishwasher, comprising:

a cabinet;

a tub provided in the cabinet to provide a washing space;

a door for opening or closing the tub;

a flow path unit for circulating air inside the tub through a suction port and an exhaust port communicating with the tub;

a heating unit comprising: a suction duct for communicating with the suction port; an exhaust conduit for communicating with the suction conduit and the exhaust port; at least two heaters provided inside the exhaust duct for heating air and controlled independently of each other so as to adjust the temperature of the air; and a fan for supplying air to the heater; and

a cap detachably provided on at least one of the suction port or the exhaust port for assisting in smoothly collecting air and discharging air, and including: a plurality of drain holes formed in an outer portion of the cap, and through which wash water introduced into the cap is discharged; and a plurality of passages provided in an inner portion of the cap and through which air passes,

wherein the flow path unit includes: a suction flow path for interconnecting the suction port and the suction duct; and an exhaust gas flow path for connecting the exhaust port and the exhaust duct to each other,

wherein the door is opened at least once during the operation of the heater when the humidity inside the dishwasher is higher than a reference humidity, and the door is closed when the humidity inside the dishwasher is lower than the reference humidity,

wherein the at least two heaters are operated while the door remains open, and

wherein the door is kept open when the air inside the tub reaches a reference humidity.

2. A dishwasher according to claim 1, wherein the heater is a Positive Temperature Coefficient (PTC) heater.

3. A dishwasher according to claim 1, wherein the RPM of the fan is changed at least once during operation of the heater.

4. The dishwasher according to claim 3, wherein the door opens in synchronization with a change in RPM of the fan.

5. A dishwasher according to claim 3, wherein the RPM of the fan after the door is opened is greater than the RPM of the fan before the door is opened.

6. The dishwasher according to claim 1, wherein each of the suction flow path and the exhaust flow path extends upward from the suction port or the exhaust port at a designated distance so as to prevent introduction of wash water.

7. The dishwasher of claim 1 wherein the suction port is positioned higher than the exhaust port.

8. A machine according to claim 6 wherein the exhaust flow path is ribbed to assist the flow of air from the exhaust duct to the exhaust port.

9. The dishwasher according to claim 6, further comprising:

an upper shelf disposed inside the tub; and

a lower shelf arranged below the upper shelf,

wherein the exhaust port is located at the same height as the lower shelf.

10. The dishwasher according to claim 6, wherein circumferential surfaces forming the suction port and the exhaust port are inclined toward the tub so as to drain the washing water introduced into the suction port and the exhaust port toward an inside of the tub.